Refining hydrocarbon oils



1,641,546 Sept. 6 1927 P. McMlcl-IAEL REFINING HYDROCARBON OILS Filed May 25, 1925 c? MYMYM f ATTORNEYS Patented Sept. 6i, 1927.

UNITED STATES PAUL MOMICHAEL, OF FLUSHING, NEW YORK, ASSIGNOR TO THE HYDROCARBON RE- FINING PROCESS CO., INC., OF NEW YORK, N. Y., A CORPORATION OE NEW YORK.

REFINING HYDROCARBON OILS.

Application 1ed` May 25d, l1925. Serial No. 32,565.

This invention relates to improvementsin the refining of petroleum hydrocarbons,.

and more -particularly relates to an improved method for refining light petroleum oils and 5 distillates, especially gasoline containing cracked oils and pressure distillates. The process of the invention is particularly applicable to the treatment of 'cracked oils such as those resulting from the cracking of certain California crude oils, the gasoline from which when obtained by the commonly used refining process `employing sulphuric acid and sodium plumbite frequently becomes discolored upon standing exposed to 15. light becoming dark yellow or even reddish brown with concurrent precipitation of gummy substances. Theprocess of the invention, however, is also useful in refining other petroleum oils, particularly light cracked oils.

For many commercial purposes, gasoline 1s `lconsidered satisfactory if it passes certam tests as to color, corrosive properties and sulphur content. Gasoline intended for use as a motor fuel is usually considered to be of satisfactory merchantable quality if in color it is equal to or better than 22 on the Saybolt universal chronometer scale (A. S. T. M. tentative method of test-serial designa- 3o tion D. 15G-23T), if itdoes not discolor a strip of mechanically polished pure sheet copper after being heated therewith for 3 method of test-serial designation D. 130- `v 22T), and if on being shaken thoroughly phur is discolored (Doctor Test for Gaso' yline--page 605 bulletin No. 17 vof the Kansas City. Testing Laboratory) Hitherto, the general practice in the rening of petroleum oils such as gasoline and gasoline containing fractions has 'involved treatment of the oil with sulphuric acid. The methods of acid treatment commonly employed have severalI disadvantages. For

hours at 122 F. (A. S. T. M; tentativey example, the acid treatment as usually ,car-

ried out tends tointroduce sulphur into the sulphuric acid tends substantiallyv to denude the oil of unsaturated constituents. Unsaturated compounds such as oleiines constitute an excellent and advantageous constituent for motor'fuel and their removal introduces -an unnecessary loss. Furthervmore, difiiculties in disposing of waste acid and acid sludge also are encountered.

It has frequently been observed that certain petroleum distillates, especially those obtained from the cracking distillation ofl certain California crude oils, tend to become discolored with relative rapidity, turning yellow or even. reddish brown, especially upon exposure to direct sun light, and usually with separation of gummy' substances, even after these distillates have been refined according to one or another Aof the commonly used methods that involve the use of sulphuric acid and sodium plumbite. -The research leading up to this invention indicated that this tendency to form gummy substances and to discolor might be related to the presence of selenium as a constituent of the oil, and the improved process of the invention provides for the substantially complete removal of any selenium present. The

invention, however, is not predicated upon this premise.

According to `the present invention, the oil to be refined is subjected to treatment with sulphur dioxide gas and is then sub# jected to treatment with an absorbent material such as fullers earth. The treatment with absorbent material advantageously follows the treatment with sulphur dioxide -gas before the oilis subjected to any other treatment. Following the treatment with absorbent material, the oil may be washed with water, and the washing operation may include treatment with an alkaline solution such as a dilute solution of sodium hydrox- 1de or more advantageously of ammonia, to

, remove any traces of sulphur dioxide remaining. Following the treatment with absorbent material, the oil may be subjected to further chemical treatment, for example, it may be subjected to treatment with an alkaline hypochlorite solution or to treatment with an alkaline plumbite solution. F ollowing the treatment with absorbent material, or following subsequent chemical treatment, the oil may be distilled.

The invention will be further described in connection with the accompanying drawings, which illustrate in a diagrammatic manner one form of apparatus adapted for carrying out the process of the invention, but it will be understood that other and different apparatus can be employed and that the invention is not limited to operations carried out in apparatus of the character illustrated.

The apparatus illustrated in the drawing comprises a treater for contacting the oil with sulphur dioxide gas and filters for filtering the oil through absorbent material after the treatment with sulphur dioxide gas. Where the oil issubjected to further chemical treatment or is redistilled following the treatment with absorbent material, the further refining operations may be carried out in any of the well known formsY of apparatus.

by means of Referring to the drawing, the oil to be4 treated is supplied through connection 1 and pump 2 is forced through pipe 3 to the upper end of the treater 4 and after flowing downwardly therethrough is then forced through one or the other of the filters 5 and 6. The oil escapes from the lower end of the treater through pipe 7. A distributor 8 for introducing sulphur .dioxide gas is arranged somewhat above the lower end of the treater. and a pump 9 is provided for forcing sulphur dioxide gas through pipe l0 and into the treater through the distributor 8. One or more screens or other distribution promoting means 11 may also be arranged above the distributor to further pro-` mote distribution of sulphur dioxide throu h the oil fiowing. downwardly through t e treater. The sulphur dioxide gas rises through the oil in the treater. and the unconsumed gas escapes through pipe 12 and is recirculated through the oil by means of pump 9 together` with fresh sulphur dioxide gas supplied through connection 13. A safety valve 14 is provided to prevent excessive rise of pressure in the treater and a level gage l5 is arranged for controlling the level of oil in and the flow of oil through the treater. The oil escaping from the lower end of the' treater through connection 7 is forced through one ofthe filters by means of pump 16. 'IWvo or more filters are provided so that the operation can be carried mareas out in a continuous manner, one or more of the filters being used for treatment of the oil while others of the filters are being charged with absorbent material or discharged after the absorbent material is no longer active. The oil escapes from the filters through connection 17 In operation, the treater is kept substantially full of oil to provide for maximum contact of the oil with the sulphur dioxide gas in the treater and the oil is forced through the treater at a rate sufficient to allow the necessary period of contact with the sulphur dioxide gas with concurrent regulation of the rate of circulation of the sulphur dioxide gas. Vigorous agitation is maintained in the treater by the rising gas currents and the sulphur dioxide is thus intimately contacted with the oil. lThe sulphur dioxide gas introduced through connection 13 may be supplied from any suitable source, for example from a burner of any of the 4known types in which sulphur is burned to form sulphur dioxide. Following the treatment with sulphur dioxide gas, the oil as it escapes from the treater is subjected to treatment with absorbent material. 1n the apparatus illustrated, this treatment is carried out by forcing the oil through a filter bed of the absorbent material. The

treatment with absorbent material, however.

may be carried out in other Ways, for example, the oil may be agitated with a portion of the absorbent material, and the absorbent material then separated by filtration or by settling followed by filtration. Suitable absorbent materials include fullers earth, infusorial earth, silica gel and the like. Fullers earth is particularly advantageous. The oil as it escapes from the treater is usually discolored tending to be more or less blackish. immediate treatment with absorbent material, in accordance with the invention, removes this discoloration and such impurities as tend to cause it. If the oil is subjected to treatment with water, as in a Washing operation, after the treatment with sulphur dioxide gas and before the treatment with absorbent material, the im urities present apparently undergo some c ange which renders them more difficult to remove on subsequent treatment with absorbent material and the oil may retain its tendency to discolor on standing and on exposure to light. The treatment with absorbent material is accordingly best carried out before the oil is subjected to any further treatment after the treatment with sulphur dioxide gas. After treatment with the absorbent material, the oil is washed With one or more portions of Water, and may also be washed with a mild alkaline solution to assist in `theremoval of any traces of sulphur dioxide or other acidic constituents. In some cases the oil at this stage may be of satisfactory quality, but

usually it will not meet the doctor test due to the presence of mercaptans or similar sulphur compounds. To remove these compounds, the oil may be subjected to further an oil of better color is desired, the oil may be distilled following 'the chemical treatment. In the case of light oils this distillation is advantageously carried out with steam, and may be carried out in the presence of some alkaline substance such as milk of lime. As much as 98% or more by volume of the oil subjected to distillation may be taken oll as distillate, but the percentage taken off as distillate will depend upon the boiling range of the oil subjected to distillation and upon the boiling range of the iinished product desired.

. The invention will be further illustratedV by the following example, but it will be understood that this more detailed illustration is for the purpose of exemplication and that the invention is not limited thereto. A

naphtha character distillate from a California crude oil was saturated with sulphur dioxidegas, was then immediately filtered through fullers earth, and was then washed with successive'portions of water until neutral. The gum content, after evaporation of 100 cc. in a hemispherical copper dish, was v reduced from about 0.072 grams to about 0,021 grams, the sulphur content originallyl 0.123% by Weight was then 0.091% by Weight, and the color determined by the Saylet bolt universal chronometer, was 22. The oil v gave an unsatisfactory .doctor test.

Cne part of this oil was then agitated for about 30 minutes with about 25% by volume of a 5% solution of sodium hypochlorite containing some free caustic soda and then with several successive portions of.

'of an alkaline solution of sodium plumbite prepared by agitating'a 20`B. solution of causticvsoda with an excess of litharge and allowing the undissolved litharge to settle out decanting the clear caustic soda solution of sodium plumbite. After agitation of the oil -with the caustic soda solution of sodium plumbite the mixture was allowed to stand several hours until the lead sulphide that formed had settled out and the caustic soda. solution of sodium plumbite was then drawn off together with the precipitated impurities and the oil was washed with several successive portions of water. l The oil then gave a satisfactory doctor test, had a color of 21, showed a sulphur content of 0.064% by weight, and a gum content of 0.017 grams. This oil was then subjected to dis- 4tillation with steam and about 98% by volume was taken oii' asY distillate. The distillate so obtained gave a satisfactory doctor test and corrosion test, had a color of 25, showed a sulphur content of 0.041% and had a gum content of 0.014 grams.

It will thus be seen that they invention provides an improved method of rening hydrocarbon oils, particularly light petroleum oils, by which they can be rendered of satisfactory merchantable quality in an eiiicient and effective manner and the invention has the further advantage that the oils so refined, particularly cracked oils produced from California crudes of the type above referred to, are of improved stability.

I claim:

1. An improved method of refining vcracked hydrocarbon oils, which comprises subjecting the oil to treatment with sulphur dioxide gas, and thereafter before any further treatment subjecting the oil to treatment with an absorbent material.

2. An cracked hydrocarbon oils, which comprises subjecting the oil to treatment with sulphur dioxide gas, and thereafter before any further treatment subjecting the oil to treatment with fullers'earth.

3. An improved method of refining vcracked hydrocarbon oils, which comprises subjecting the oil to treatment with sulphur dioxide gas, then subjecting the oil to treatment with an absorbent material and thereafter washing" it with water.

4. An improved I. method of refining cracked hydrocarbon oils, which comprises subjecting the oil to treatment with sulphur dioxide gas, then subjecting the oil to treatment with an absorbent material and thereafter washing it with water and with an aqueous alkaline solution.

5. An improved method of refining cracked hydrocarbon oils, which comprises subjecting the oil to treatment with sulphur dioxide gas, then successively subjecting the Aoil to-treatment with an absorbent material,

to a water wash, and to a treatment with a refining agent for the removal of sulphur.

6. An improved method of refining improved method of refining cracked hydrocarbon oils, which comprises 7; An improved method of refining subjecting the oil to treatment with sulphur cracked hydrocarbon oils, which comprises dioxide gas, then successively subjecting the subjecting the oil to treatment with sulphur l@ oil to treatment with an absorbent material, dioxide gas and then to treatment with an to a Water wash, and to a treatment with a absorbent material.

rening agent for the removal of sulphur, In testimony whereof l aix my signature. and thereafter distilling the treated oil. PAUL MCMICHAEL. 

